wiktionary schedulingScheduling is the process of deciding how to commit resources between a variety of possible tasks. Time can be specified scheduling a flight to leave at 8 00 or floating as part of a sequence of events. The word may also refer to I O scheduling , the order in which I O requests are submitted to a block device in Computer Operating Systems Broadcast programming Scheduling broadcasting , the minute planning of the content of a radio or television broadcast channel Scheduling algorithm Scheduling computing , the way various processes are assigned in multitasking and multiprocessing operating system design Scheduling production processes , the planning of the production or the operation Schedule workplace , ensuring that an organization has sufficient staffing levels at all times Job scheduler , an enterprise software application in charge of unattended background executions. Job Shop Scheduling , an optimization problem in computer science. See also Schedule disambiguation Timetable disambiguation Notation for theoretic scheduling problems Calendaring software disambig de Scheduler fr Ordonnancement ko sv Schemal ggning ... more details
Lottery Scheduling is a Probability probabilistic Scheduling computing scheduling algorithm for Computer process processes in an operating system . Processes are each assigned some number of lottery ticket s, and the scheduler draws a random ticket to select the next process. The distribution of tickets need not be uniform granting a process more tickets provides it a relative higher chance of selection. This technique can be used to approximate other scheduling algorithms , such as Shortest job next and Fair share scheduling . Lottery scheduling solves the problem of Resource starvation starvation . Giving each process at least one lottery ticket guarantees that it has non zero probability of being selected at each scheduling operation. Implementation Implementations of lottery scheduling should take into consideration that there could be billions of tickets distributed among a large pool of threads. To have an array where each index represents a ticket, and each location contains the thread corresponding to that ticket, may be highly inefficient. Lottery scheduling can be preemptive or non preemptive. See also Scheduling computing External links http inst.eecs.berkeley.edu cs162 sp06 Operating systems and systems programming UC Berkeley OS Class http www.usenix.org events usenix99 full papers petrou petrou.pdf Implementing Lottery Scheduling Matching the Specialization in Traditional Schedulers Paper by David Petrou et al. Category Scheduling algorithms de Lotterie Scheduling ... more details
Unreferenced date December 2006 Timebar scheduling is a method of staff schedule workplace scheduling that may be adopted by organization s with highly variable Employee staff scheduling requirements. The primary advantage of timebar scheduling is that it makes it visually clear how many employees will be working or on break at any given time. To implement timebar scheduling, employee staff names identifiers are listed on the vertical axis of a page, and horizontal time bars are drawn perpendicular to the staff s names. The start time and length of each work period allocated to the staff member is represented by the time bar. See also Portal Organized labour Shift work Project planning References Reflist DEFAULTSORT Timebar Scheduling Category Employment ... more details
unreferenced date February 2008 In parallel computing , loop scheduling is the problem of assigning proper iterations of parallelizable loops among n processors to achieve Load balancing computing load balancing and maintain Locality of reference data locality with minimum dispatch overhead. Typical loop scheduling methods are static even scheduling evenly divide loop iteration space into n chunks and assign each chunk to a processor dynamic scheduling a chunk of loop iteration is dispatched at runtime by an idle processor. When the chunk size is 1 iteration, it is also called self scheduling. guided scheduling similar to dynamic scheduling, but the chunk sizes per dispatch keep shrinking until reaching a preset value. See also OpenMP Automatic parallelization Loop nest optimization Category Parallel computing ... more details
In computer science , a scheduling algorithm is the method by which Thread computer science threads , Process computing processes or data Flow computer networking flows are given access to system resources e.g. processor time, communications bandwidth . This is usually done to Load balancing computing load balance a system effectively or achieve a target quality of service . The need for a scheduling algorithm arises from the requirement for most modern systems to perform computer multitasking multitasking execute more than one process at a time and multiplexing transmit multiple flows simultaneously . In computing and multitasking The algorithm used may be as simple as Round robin scheduling ... , the notion of a scheduling algorithm is used as an alternative to FIFO computing first come first served queuing of data packets. The simplest best effort scheduling algorithms are round robin scheduling round robin , fair queuing a max min fair scheduling algorithm , proportionally fair scheduling and maximum throughput scheduling maximum throughput . If differentiated or guaranteed ... 3.5G cellular system, channel dependent scheduling may be used to take advantage of channel state ... may be increased. In even more advanced systems such as LTE Advanced LTE , the scheduling is combined ... Atropos scheduler Completely Fair Scheduler Dynamic priority scheduling Earliest deadline first scheduling Foreground background I O scheduling Job Shop Scheduling Least slack time scheduling Lottery scheduling Multilevel feedback queue O 1 scheduler Rate monotonic scheduling Round robin schedulingScheduling communications Scheduling computing External links http joshaas.net linux Josh Aas introduction ... results for scheduling problems http www.mathematik.uni osnabrueck.de research OR class http rtime.felk.cvut.cz scheduling toolbox TORSCHE Scheduling Toolbox for Matlab is a toolbox of scheduling and graph algorithms. Category Scheduling algorithms Category Planning es Algoritmo de planificaci n he ... more details
Unreferenced date December 2009 Orphan date December 2009 The basic idea of list scheduling is to make an ordered list of processes by assigning them some priorities, and then repeatedly execute the following two steps until a valid schedule is obtained Select from the list, the process with the highest priority for scheduling. Select a resource to accommodate this process. The priorities are determined statically before scheduling process begins. The first step chooses the process with the highest priority, the second step selects the best possible resource. Some known list scheduling strategies are Highest level first algorithm or HLF Longest path algorithm or LP Longest processing time Critical path method DEFAULTSORT List Scheduling Category Scheduling algorithms ... more details
In computer science , multiprocessor scheduling is an NP Complete optimization problem. The problem statement is Given a set J of jobs where job j sub i sub has length l sub i sub and a number of processors m sub i sub , what is the minimum possible time required to schedule all jobs in J on m processors such that none overlap? cn date March 2011 The applications of this problem are numerous, but are, as suggested by the name of the problem, most strongly associated with the scheduling computing scheduling of computational tasks in a multiprocessor environment. Algorithms A simple, often used algorithm is the LPT Algorithm Longest Processing Time which sorts the jobs by its processing time and then assigns them to the machine with the first end time. This algorithm achieves a sharp bound of 4 3 1 3m OPT. ref name stanford http www.stanford.edu class msande212 Lectures Lecture10.pdf ref See also Job shop scheduling , a similar problem for scheduling jobs on machines. Some variants of multiprocessor scheduling and job shop scheduling are equivalent problems. merge these two articles? References references A compendium of NP optimization problems. Editors Pierluigi Crescenzi, and Viggo Kann http www.ensta.fr diam ro online viggo wwwcompendium node180.html Category Scheduling computing Category Mathematical optimization comp sci stub pl Optymalne szeregowanie zada dla wielu procesor w ... more details
Unreferenced date December 2009 In control theory , gain scheduling is an approach to control of non linear system s that uses a family of linear Controller control theory controller s, each of which provides satisfactory control for a different operating point of the system. One or more observable variables, called the scheduling variables, are used to determine what operating region the system is currently in and to enable the appropriate linear controller. For example in an aircraft flight control system , the altitude and Mach number might be the scheduling variables, with different linear controller parameters available and automatically plugged into the controller for various combinations of these two variables. It is one of the simplest and most intuitive forms of adaptive control . DEFAULTSORT Gain Scheduling Category Nonlinear control Category Control theory Category Control engineering Category Classical control ar es Planificaci n de ganancias fr S quencement de gain it Gain scheduling ... more details
Orphan date February 2009 Wikify date April 2010 Hybrid Scheduling is a class of scheduling mechanisms that mix different scheduling criteria or disciplines in one algorithm. For example, scheduling uplink and downlink traffic in a Wireless LAN WLAN Wireless Local Area Network, such as IEEE 802.11e using a single discipline or framework is an instance of hybrid scheduling. Other examples include a scheduling scheme that can provide differentiated and integrated guaranteed services in one discipline. Examples of such schedulers are found in the following articles 1 Y. Pourmohammadi Fallah, H. Alnuweiri, http www.sciencedirect.com science? ob MImg& imagekey B6WKJ 4M0J4HN 1 1& cdi 6908& user 1022551& orig search& coverDate 02 28 2007& sk 999329997&view c&wchp dGLzVlz zSkzV&md5 d579644a4e51b4821fa2718cf96940ff&ie sdarticle.pdf Hybrid Polling and Contention Access Scheduling in IEEE 802.11e WLANs , Journal of Parallel and Distributed Computing, Elsevier, Vol 67, Issue 2, Feb. 2007, pp. 242 256. Category Computer networking ... more details
In Computer science , Gang scheduling is a scheduling algorithm for parallel systems that schedules related thread computer science thread s or process computing process es to run simultaneously on different central processing unit processor s. Usually these will be threads all belonging to the same process, but they may also be from different processes, for example when the processes have a producer consumer relationship, or when they all come from the same Message Passing Interface MPI program. Gang scheduling is used so that if two or more threads or processes communicate with each other, they will all be ready to communicate at the same time. If they were not gang scheduled, then one could wait to send or receive a message to another while it is sleeping, and vice versa. When processors are over subscribed and gang scheduling is not used within a group of processes or threads which communicate with each other, it can lead to situations where each communication event suffers the overhead of a context switch. Technically, gang scheduling is based on a data structure called the Ousterhout matrix. In this matrix each row represents a time slice, and each column a processor. The threads or processes of each job are packed ref Dror G. Feitelson 1996 . http dx.doi.org 10.1007 BFb0022289 Packing schemes for gang scheduling . In Job Scheduling Strategies for Parallel Processing, Springer ... in one row to those in the next row. Gang scheduling is stricter than Coscheduling . ref ...&rep rep1&type pdf Gang Scheduling Performance Benefits for Fine Grain Synchronization . Journal ... that do not run concurrently with the rest of the gang. Gang scheduling was implemented and used ... Scheduling, Timesharing on Parallel Computers, SC98, November 1998 a summary http www.llnl.gov asci pse trilab sc97.paper.html Performance Characteristics of Gang Scheduling in Multiprogrammed Environments, SC97, November 1997 reflist DEFAULTSORT Gang Scheduling Category Scheduling algorithms comp sci ... more details
Unreferenced stub auto yes date December 2009 Trace scheduling is an Compiler optimization optimization technique used in compilers for computer programs . A compiler often can, by Instruction scheduling rearranging its generated machine instruction s for faster execution, improve program performance. Trace scheduling is one of many known techniques for doing so. Trace scheduling was originally developed for Very Long Instruction Word, or VLIW machines, and is a form of global code motion. It works by converting a loop to long straight line code sequence using loop unrolling and static branch prediction . This process separates out unlikely code and adds handlers for exits from trace. The goal is to have the most common case executed as a sequential set of instructions without branches. DEFAULTSORT Trace Scheduling Category Compiler optimizations Category Compiler construction Prog lang stub it Trace scheduling ja ... more details
Unreferenced date January 2009 In computer science , instruction scheduling is a compiler optimization used to improve instruction level parallelism, which improves performance on machines with instruction pipeline s. Put more simply, without changing the meaning of the code, it tries to Avoid pipeline stall s by rearranging the order of instructions. Avoid illegal or semantically ambiguous operations typically involving subtle instruction pipeline timing issues or non interlocked resources. order the instructions to avoid duplicated memory access This doesn t belong in instruction scheduling The pipeline ... scheduling is typically done on a single basic block . In order to determine whether rearranging ... However, we want more than a valid instruction scheduling we also want one which minimizes delays ... used and is known as list scheduling . Conceptually, it repeatedly selects a source of the dependency ... cause other vertices to be sources, which will then also be considered for scheduling. The algorithm ... of Instruction Scheduling Instruction scheduling may be done either before or after register allocation ... after register allocation. This second scheduling pass will also improve the placement of the spill fill code. If scheduling is only done after register allocation then there will be false dependencies .... Types of Instruction Scheduling There are several types of instruction scheduling Local Basic Block Scheduling instructions can t move across basic block boundaries. Global scheduling instructions can move across basic block boundaries. Modulo Scheduling another name for software pipelining , which is a form of instruction scheduling that interleaves different iterations of a Control flow Loops loop . Trace scheduling the first practical approach for global scheduling, trace scheduling tries to optimize the control flow path that is executed most often. Superblock scheduling a simplified form of trace scheduling which does not attempt to merge control flow paths at trace side ... more details
Unreferenced date January 2009 A scheduling alliance is agreement among independent college athletics college athletic teams to guarantee a set number of games to each member. Although it is not formally recognized by the governing body usually the National Collegiate Athletic Association NCAA , it resembles a Conference sports conference in many respects. The scheduling alliance may be very informal, only involving guaranteed games, or it may have awards, such as player of the week, MVP and a championship title. sports stub Category College sports in the United States ... more details
Interval scheduling is a class of problems in computer science , particularly in the area of algorithm design. A list of tasks is given as a set of time intervals for instance, one task might run from 2 00 to 5 00 and another task might run from 6 00 to 8 00. Posed as an optimization problem, the goal is to maximize the number of executed tasks without overlapping the tasks. A request corresponds to an interval of time. We say that a subset of requests is compatible if no two of them overlap in time and our goal is to accept as large a compatible subset as possible. Compatible set of maximum size are called optimal. There are several solutions for this problem that are not optimal. For example, selecting the intervals that start earliest is not an optimal solution because if the earliest interval happens to be really long by accepting it we would have to reject other many shorter requests. Also, selecting the shortest intervals is not optimal either or selecting intervals with fewest conflicts. The optimal solution is choosing the earliest finishing time, as in the request that finishes first. One way of proving the optimality of this algorithm is by using the Charging Argument . An important class of scheduling algorithms is the class of dynamic priority algorithms. When none of the intervals overlap the optimum solution is trivial. The optimum for the non weighted version can found with the earliest deadline first scheduling . Weighted interval scheduling is a generalization where a value is assigned to each executed task and the goal is to maximize the total value. The solution need not be unique. See also Scheduling computing Earliest deadline first scheduling Sources cite book first Jon last Kleinberg coauthors Tardos, Eva title Algorithm Design year 2006 isbn 0 321 29535 8 Category Scheduling algorithms ... more details
Unreferenced date November 2006 Context date October 2009 Stride scheduling mechanism has been introduced as a simple concept to achieve proportional Central processing unit CPU capacity reservation among concurrent processes. Stride scheduling aims to sequentially allocate a resource for the duration of standard time slices quantum in a fashion, that performs periodic recurrences of allocations. Thus, a process p1 which has reserved twice the share of a process p2 will be allocated twice as often as p2. In particular, process p1 will even be allocated two times every time p2 is waiting for allocation, assuming that neither of the two processes performs a blocking operation . DEFAULTSORT Stride Scheduling Category Central processing unit Compsci stub ... more details
Mergeto blocking computing date February 2009 In a Computer multitasking multitasking computer system, individual tasks, or threads of execution, must share the resources of the system. These resources might be the CPU network memory disk or any other shared resource. When one task is using a resource, it is generally not possible, or desirable, for another task to access it. The techniques of mutual exclusion are often used to prevent one piece of software using a resource before another has finished with it. When this occurs, the second task is said to be blocked , and is unable to execute until the first task has finished using the shared resource. Programming languages and scheduling algorithms are designed to minimize this blocking, and to prevent the case of deadlock , where two or more tasks are blocked, waiting for a resource that the other holds. See also Non blocking synchronization Concurrent computing Race condition Computing Race condition Deadlock Scheduling computing Category Scheduling computing ... more details
Meta scheduling or Super scheduling is a computer software technique of optimizing computational workloads by combining an organization s multiple Distributed Resource Manager s into a single aggregated view, allowing batch job s to be directed to the best location for execution. Implementations The following is a partial list of noteworthy open source and commercial meta schedulers currently available. GridWay by the Globus Alliance http grid1.jlu.edu.cn csf Community Scheduler Framework by Platform Computing & Jilin University MP Synergy by United Devices Moab Cluster Suite and Maui Cluster scheduler from http www.adaptivecomputing.com Adaptive Computing http diogenes.grid.pub.ro DIOGENES DIstributed Optimal GENEtic algorithm for grid applications Scheduling, started project SynfiniWay s meta scheduler. References cite web url http www.mcs.anl.gov schopf Pubs sched.arch.2002.pdf format pdf last Schopf first Jennifer title A General Architecture for Scheduling on the Grid publisher Argonne National Laboratory year 2002 External links http apstc.sun.com.sg content.php?l1 research&l2 projects&l3 supsched Super Scheduler project by the Asia Pacific Science Technology Center. Category Grid computing compu stub ... more details
refimprove date February 2011 wikify date February 2011 Crew scheduling is the process of assigning crews to operate transportation systems, such as rail lines or aircraft. Complex Most transportation systems use software to manage the crew scheduling process. Crew scheduling becomes more and more complex as you add variables to the problem. These variables can be as simple as 1 location, 1 skill requirement, 1 shift of work and 1 set roster of people. In the Transportation industries, such as Rail or mainly Air Travel, these variables become very complex. In Air Travel for instance, there are numerous rules or constraints that are introduced. These mainly deal with legalities relating to work shifts and time, and a crew members qualifications for working on a particular aircraft. Add numerous locations to the equation and Collective Bargaining and Federal labor laws and these become new ... for any crew scheduling solution. 4 Parts Although not a rule , We can describe at least 4 parts of the equation ..., including Shift hours and seniority. br In crew scheduling the rules and constraints are typically ... of scheduling awareness until the end of each scheduling period is a major workforce issue and an employee .... The newest approach to PBS and crew scheduling takes advantage of the interaction possible ... algorithm to do so , interactive live PBS crew scheduling is the next step. the internet and it s reach are starting to change crew scheduling within the large, global organizations that use ... s Largest Crew Scheduling Problem ref Distruptions Additional unplanned disruptions in schedules due to weather and air traffic control delays can disrupt schedules, so crew scheduling software remains ... crew Scheduling under Uncertainty ref Related topics systems Preferential bidding system Fatigue safety Automated planning and scheduling Related topics algorithms and software Linear programming Column generation Tabu search Fatigue Avoidance Scheduling Tool List of crew scheduling software ... more details
Anticipatory scheduling is an algorithm for scheduling hard disk input output . It seeks to increase the efficiency of disk utilization by anticipating synchronous read operations. Deceptive idleness is a situation where a process computing process appears to be finished reading from the disk when it is actually processing data in preparation of the next read operation. This will cause a normal work conserving I O scheduler to switch to servicing I O from an unrelated process. This situation is detrimental to the throughput of synchronous reads, as it degenerates into a seeking workload. ref cite paper author Iyer, Sitaram title The Effect of Deceptive Idleness on Disk Schedulers url http scholarship.rice.edu handle 1911 17433 accessdate 2010 04 20 ref Anticipatory scheduling overcomes deceptive idleness by pausing for a short time a few milliseconds after a read operation in anticipation of another close by read requests. ref cite mailing list last Morton first Andrew authorlink Andrew Morton computer programmer title 2.5.59 mm5 mailinglist linux kernel, linux mm date 2003 01 23 url http kerneltrap.org node 567 accessdate 2007 05 23 ref Anticipatory scheduling yields significant improvements in disk utilization for some workloads. ref cite mailing list last Morton first Andrew authorlink Andrew Morton computer programmer title IO scheduler benchmarking mailinglist linux kernel date 2003 02 20 url http kerneltrap.org node 592 accessdate 2007 05 23 ref In some situations the Apache web server may achieve up to 71 more throughput from using anticipatory scheduling. ref cite conference last Iyer first Sitaram coauthors Druschel, Peter title Anticipatory scheduling A disk scheduling ... Linux 2 6 33 title Linux 2 6 33 Linux Kernel Newbies ref See also Scheduling computing Other I O schedulers ... Category Operating system kernels Category Disk scheduling algorithms fr Anticipatory scheduling DEFAULTSORT Anticipatory Scheduling ... more details
About processes assignment in operating systems other uses Scheduling disambiguation Cleanup date April 2008 Scheduling is a key concept in computer multitasking , multiprocessing operating system and real time operating system designs. Scheduling refers to the way Process computing processes are assigned ... time scheduling, modern GUI interfaces would seem sluggish. Stallings, 399 . Long term scheduling is also ... to assist these functions, in addition to any underlying admission scheduling support in the operating ... programming signal . Thus the short term scheduler makes scheduling decisions much more frequently than the long term or mid term schedulers a scheduling decision will at a minimum have to be made after ... component involved in the CPU scheduling function is the dispatcher. The dispatcher is the module ... another running is known as the dispatch latency . Gravin, 155 . Scheduling disciplines Main Scheduling algorithm Scheduling disciplines are algorithms used for distributing resources among parties which simultaneously and asynchronously request them. Scheduling disciplines are used in router s to handle ... science threads and process computing processes , disk drives I O scheduling , printers print spooler , most embedded systems, etc. The main purposes of scheduling algorithms are to minimize resource starvation and to ensure fairness amongst the parties utilizing the resources. Scheduling deals with the problem ... different scheduling algorithms. In this section, we introduce several of them. First in first out Main First In First Out Also known as F irst C ome, F irst S erved FCFS , is the simplest scheduling ..., scheduling overhead is minimal. Throughput can be low, since long processes can hog the CPU ..., especially in a busy system with many small processes being run. Fixed priority pre emptive scheduling Main Fixed priority pre emptive scheduling The O S assigns a fixed priority rank to every process ... is it significant. FPPS has no particular advantage in terms of throughput over FIFO scheduling. Waiting ... more details
Aging is the process of gradually increasing the priority of a Task computing task , based on its waiting time. The aging technique estimates the time a process will run based on a weighted average of previous estimates and measured values. ref Tanenbaum AS 2008 Modern Operating Systems , 3rd ed., p. 158. Pearson Education, Inc. ISBN 0 13 600663 9 ref Aging can be used to reduce Starvation computing starvation of low priority tasks. ref http www.comsci.us os notes ch08.html Processor Scheduling Notes Operating Systems Computer Science Now Bot generated title ref References reflist Category Scheduling computing operating system stub aging is used to ensure that jobs in the lower level queues will eventually complete there execution ... more details
Refimprove date April 2008 Block scheduling is a type of academic scheduling in which each student has ... called a mini mester . Conversion to block scheduling became a relatively widespread trend in United ... 40 60 minutes long, but under block scheduling, they became approximately 90 minutes long. However ... scheduling to be a dubious education reform scheme. Citation needed date June 2010 Part of the motivation for block scheduling is to prepare students for taking end of grade end of course standardized ... scheduling Time Quarter 1 Quarter 2 Quarter 3 Quarter 4 08 00 09 25 rowspan 1 English 1 rowspan ... collapse float right margin left 2em margin bottom 1em colspan 6 Other example of block scheduling ... bottom 1em colspan 4 Another example of block scheduling Time Semester 1 Semester 2 08 30 10 00 rowspan ... 1 Clear One way of doing block scheduling, called A B block scheduling, is shown in the example ... called 4 4 block scheduling splits the academic year into quarters, and uses a four period day. ref ... block scheduling resulted in higher cross subject achievement than traditional schedules. However, the outcome ... who had block scheduling in high school performed worse in college science courses. ref name Tai http www.virginia.edu insideuva 2006 08 block scheduling.html Block scheduling Not helping high school students perform better in college science by Robert Tai ref A systematic review on Block Scheduling ... evidence to support the introduction of policy guidance on the use of block scheduling in secondary ... scheduling strong enough to recommend their implementation. ref http eppi.ioe.ac.uk cms Default.aspx?tabid 2476 ref Criticism Block scheduling has both advocates and critics, based on different perceptions ... is standardized to manage all students in a single scheduling framework. Class length The system ... from a lack thereof. ref name Lindsay Block scheduling can result in gaps of a day or days or even ... Against Block Scheduling by Jeff Lindsay engineer Jeff Lindsay ref Some observers similarly feel ... more details
Event scheduling is the activity of finding a suitable time for an event such as meeting, conference, trip, etc. It is an important part of event planning that is usually carried out at its beginning stage. In general, event scheduling must take into account what impact particular dates of the event could have on the success of the event. When organizing a scientific Academic conference conference , for example, organizers might take into account the knowledge in which periods classes are held at universities, since it is expected that many potential participants are university professors. They should also try to check that no other similar conferences are held at the same time, because overlapping would make a problem for those participants who are interesting in attending all conferences. When it is well known who is expected to attend the event e.g. in the case of a project meeting , organizers usually try to synchronize the time of the event with planned schedules of all participants. This is a difficult task when there are many participants or when the participants are located at distant places. In such cases, the organizers should first define a set of suggested dates and address a query about suitable dates to potential participants. After response is obtained from all participants, the event time suitable for most of participants is selected. This procedure can be alleviated by internet tools. ref cite news last Seeley first Monica title Tackling reports publisher The Times date 2007 06 20 url http www.timesonline.co.uk tol life and style career and jobs secretarial article1954844.ece accessdate 2007 07 09 location London ref See also Event planning http www.evocos.co.uk Event Scheduling Software References Reflist Category Planning ... more details
Irrigation scheduling is the process used by irrigation system managers to determine the correct frequency and duration of watering. The following factors may be taken into consideration Precipitation rate of the irrigation equipment how quickly the water is applied, often expressed in inches or mm per hour. Distribution uniformity of the irrigation system how uniformly the water is applied, expressed as a percentage, the higher the number, the more uniform. infiltration hydrology Soil infiltration rate how quickly the water is absorbed by the soil, the rate of which also decreases as the soil becomes wetter, also often expressed in inches or mm per hour. Slope topography of the land being irrigated as this affects how quickly surface runoff runoff occurs, often expressed as a percentage, i.e. distance of fall divided by 100 units of horizontal distance 1 ft of fall per convert 100 ft m abbr on would be 1 . Soil available water capacity , expressed in units of water per unit of soil, i.e. inches of water per foot of soil. Effective root ing depth of the plants to be watered, which affects how much water can be stored in the soil and made available to the plants. Current watering requirements of the plant which may be estimated by calculating evapotranspiration , or ET , often expressed in inches per day. Amount of time in which water or labor may be available for irrigation. Amount of allowable moisture stress which may be placed on the plant. For high value vegetable crops, this may mean no allowable stress, while for a lawn some stress would be allowable, since the goal would .... The goal in irrigation scheduling is to apply enough water to fully wet the plant s root zone while ... do tend to conserve water over conventional human scheduling as the program is updated at least ... . 1 Other devices helpful in irrigation scheduling are rain sensors, which automatically shut off ... and gypsum blocks. For more information and advice on irrigation scheduling see www.irrigationworld2000.com ... more details
The scheduling of ITV soap opera Emmerdale has varied since it was first shown in 1972, increasing from two half hour episodes a week when it began to four half hour episodes and one hour long episode each week at present. It has also moved from its original afternoon slot to a prime time slot of 19 00. A few years after the start, the majority of ITV regions chose to accommodate the programme in the 19 00 Tuesday and Thursday slot. Anglia Television , Thames Television and Scottish Television preferred a Monday and Tuesday 17 15 slot and saw the week s episodes before the rest of the network. 1972 1987 There were varying seasons of Emmerdale Farm and some years only a few episodes were shown 1972 20 episodes 1973 102 episodes 1974 98 episodes 1975 61 episodes 1976 37 episodes 1977 91 episodes 1978 74 episodes 1979 52 episodes 1980 85 episodes 1981 73 episodes 1982 67 episodes 1983 71 episodes 1984 75 episodes 1985 92 episodes 1986 99 episodes 1987 99 episodes 1988 1989 From 6 January 1988, all ITV regions networked the show in the Wednesday and Thursday 18.30 slot. Anglia Television and Central Television chose to move the programme to 19 00 on Tuesdays and Thursdays in February 1989, as they were screening the new daily Australian drama Home and Away in the Emmerdale Farm slot. This was the first time Anglia had screened Emmerdale Farm in the 19 00 slot. Central were simply returning to the slots they used until December 1987. For a period Anglia and Central saw episodes one week later than other regions. During this period, the following episodes were transmitted 1988 100 episodes 1989 102 episodes 1990 1992 From January 1990 all other regions followed the Central and Anglia schedule in the familiar Tuesday and Thursday 19 00 slot. Enjoying highs of 11 million viewers. During the mid 1990s Scottish Television used the 19 00 slot to show daily regional programmes resulting in Emmerdale moving to 17 10. Scottish Television had always given preference to their own countryside ... more details
Encyclopedia
top
